This invention relates generally to organophilic clays (hereinafter referred to as "organoclays"), and more specifically relates to an improved process for manufacture of same, which process strikingly enhances the gelling properties of the said products.
Organoclays, representing the reaction product of a smectite-type clay with a higher alkyl-containing quaternary ammonium compound, have long been known for use in gelling of organic liquids such as lubricating oils, linseed oil, toluene and the like. A large variety of highly useful products, such as lubricating greases are producible through use of such gelling agents. The procedures and chemical reactions pursuant to which these organoclays are prepared, are well-known. Thus, under appropriate conditions, the organic compound which contains a cation, will react by ion exchange with clays which contain a negative layer lattice and exchangeable cations to form the organoclay products. If the organic cation contains at least one alkyl group containing at least 10 carbon atoms, then the resultant organoclays will have the property of swelling in certain organic liquids.
Among the prior art patents which discuss at length aspects of the preparation and properties of organoclays, as above outlined, are U.S. Pat. Nos. 2,531,427; 2,966,506; 3,974,125; 3,537,994; and 4,081,496. Reference may also be had to applicable portions of the standard reference work "Clay Mineralogy", 2nd Edition, 1968, by Ralph E. Grim, McGraw Hill Book Company.
In the usual procedure for preparing an organophilic clay pursuant to this prior art, the smectite-type clay, selected quaternary compound and water are mixed together, preferably at an elevated temperature, typically in the range of 100.degree. F. to 180.degree. F., for a period of time sufficient for the organic quaternary ammonium compound to coat the clay particles. Thereafter, the product can be filtered, washed, dried and ground, or otherwise processed, depending upon the intended use. In some instances, e.g., the drying and grinding step may be omitted. Various other modifications of this process may be used depending upon the form of product desired--as will be noted in the referenced patents.